Genuineness detectng system and method for using genuineness detecting film

ABSTRACT

An authenticity identifying film ( 10 ) has a reflective film ( 11 ) having a circularly polarized light selectivity to reflect at least only either of right-handed circularly polarized light and left-handed circularly polarized light of incident light to produce reflected light. The reflective film ( 11 ) is provided with a hologram forming part ( 11   a ). The hologram forming part ( 11   a ) reflects circularly polarized light of the same circular polarization as that of the reflected light in a direction different from that of the reflected light to form a holographic image. The reflected light reflected by the reflective film ( 11 ) and the holographic image formed by the hologram forming part ( 11   a ) are detected by detectors disposed at different positions, respectively.

TECHNICAL FIELD

[0001] The present invention relates to an authenticity identifying filmand authenticity identifying system for preventing the forgery ofarticles including cards, gift certificates, currency notes, tickets,bank notes, securities, betting tickets and the like, and a method ofusing the authenticity identification film.

BACKGROUND ART

[0002] A conventional method of preventing the forgery of credit cards,deeds, currency notes and the like attaches an authenticity identifyingmedium which is difficult to forge to an article to be protected fromforgery, and identifies the authenticity identifying medium visually ormechanically. A hologram or a liquid crystal film is used as theauthenticity identifying medium.

[0003] Holograms include those carrying a holographic image ofcharacters and patterns for visual identification, those carrying aholographic image of numerical codes and special patterns for mechanicalrecognition, and those carrying both the foregoing holographic images.The hologram has been prevalently used because the hologram cannot becopied by an ordinary color copying machine or the like and is effectivein forgery prevention, the hologram is attractive because of its highlyaesthetic design, the hologram is difficult to produce and hence thehologram has been prevalently used.

[0004] Previously proposed methods employing liquid crystal filmsincludes a method proposed in JP-A No. Sho 63-51193 using a cholestericliquid crystal which looks in different colors when seen from differentdirections, and a method proposed in JP-A No. Hei 8-43804 using anoptically anisotropic nematic liquid crystal. The method using acholesteric liquid crystal is able to record two characteristics of thecholesteric liquid crystal, namely, selective reflectivity and circularpolarization selectivity, as information for authenticity identificationon a single medium, mass-production of a cholesteric liquid crystal offixed properties is difficult and hence this method is excellent inforgery preventing effect.

[0005] However, recently prevalent hologram producing techniques havemade possible the production of counterfeits of conventional holograms,which reduced the forgery preventing effect of the conventionalholograms.

[0006] Although the forging of liquid crystal films is difficult, themass production of authentic liquid crystal films also is difficult, andhence liquid crystal films have not been prevalently used asauthenticity identification mediums.

DISCLOSURE OF THE INVENTION

[0007] It is an object of the present invention to provide anauthenticity identifying film having a highly esthetic design, difficultto forge and facilitating either visual or mechanical authenticityidentification, an authenticity identifying system and a method of usingthe authenticity identifying film.

[0008] An authenticity identifying film according to the presentinvention includes a reflective film having a circularly polarized lightselectivity to reflect only either of right-handed circularly polarizedlight and left-handed circularly polarized light of at least incidentlight to produce reflected light, wherein the reflective film isprovided with a hologram forming part that reflects circularly polarizedlight of the same circular polarization as that of the reflected lightin a direction different from that of the reflected light to form aholographic image.

[0009] An authenticity identifying film according to the presentinvention includes a reflective film having a circularly polarized lightselectivity to reflect only either of right-handed circularly polarizedlight and left-handed circularly polarized light of at least incidentlight to produce reflected light, and a hologram forming layer laminatedto the reflective film having a hologram forming part that reflectscircularly polarized light of circular polarization opposite that of thereflected light in a direction different from that of the reflectedlight to form a holographic image.

[0010] The authenticity identifying film according to the presentinvention is characterized in that the reflective film is a liquidcrystal film.

[0011] The authenticity identifying film according to the presentinvention is characterized in that the reflective film has a fixedcholesteric phase.

[0012] The authenticity identifying film according to the presentinvention is characterized in that the hologram forming part includes anembossed hologram.

[0013] The authenticity identifying film according to the presentinvention may further include an adhesive layer to be attached to anarticle.

[0014] The authenticity identifying film according to the presentinvention is characterized in that the reflective film is delaminatedwhen the authenticity identifying film is separated from an article.

[0015] The authenticity identifying film according to the presentinvention may further include a protective film covering a surface ofthe reflective film opposite a surface of the same facing an article.

[0016] The authenticity identifying film according to the presentinvention may further include a base film attached by an additionaladhesive layer to a surface of the reflective film opposite a surface ofthe same facing an article.

[0017] The authenticity identifying film according to the presentinvention may further include a light absorbing layer interposed betweenthe reflective film and the adhesive layer.

[0018] An article with an authenticity identifying film according to thepresent invention comprises: an authenticity identifying film includinga reflective film having a circularly polarized light selectivity toreflect only either of right-handed circularly polarized light andleft-handed circularly polarized light of at least incident light toproduce reflected light, the reflective film being provided with ahologram forming part that reflects circularly polarized light of thesame circular polarization as that of the reflected light in a directiondifferent from that of the reflected light to form a holographic image,or an authenticity identifying film including a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of at least incident light to produce reflected light,and a hologram forming layer laminated to the reflective film, having ahologram forming part that reflects circularly polarized light ofcircular polarization opposite that of the reflected light in adirection different from that of the reflected light to form aholographic image; an article to which the authenticity identifying filmis bonded; and a photograph interposed between the article and theauthenticity identifying film.

[0019] An authenticity identifying system according to the presentinvention comprises: an authenticity identifying film including areflective film having a circularly polarized light selectivity toreflect only either of right-handed circularly polarized light andleft-handed circularly polarized light of at least incident light toproduce reflected light, the reflective film being provided with ahologram forming part that reflects circularly polarized light of thesame circular polarization as that of the reflected light in a directiondifferent from that of the reflected light to form a holographic image,or an authenticity identifying film including a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of at least incident light to produce reflected light,and a hologram forming layer laminated to the reflective film, having ahologram forming part that reflects circularly polarized light ofcircular polarization opposite that of the reflected light in adirection different from that of the reflected light to form aholographic image; a light source unit that irradiates the authenticityidentifying film with light; and a detecting unit for detectingreflected light from the authenticity identifying film and theholographic image.

[0020] In the authenticity identifying system according to the presentinvention, the detecting unit is capable of detecting only light in apredetermined waveband.

[0021] In the authenticity identifying system according to the presentinvention, the detecting unit is capable of measuring the intensity oftransmitted light.

[0022] In the authenticity identifying system according to the presentinvention, at least either the light source unit or the detecting unitis provided with a polarizing plate, a phase plate or a band-passfilter.

[0023] According to the present invention, a method of using anauthenticity identifying film including a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of at least incident light to produce reflected light,the reflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film including a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofat least incident light to produce reflected light, and a hologramforming layer laminated to the reflective film, having a hologramforming part that reflects circularly polarized light of circularpolarization opposite that of the reflected light in a directiondifferent from that of the reflected light to form a holographic image,the method comprising the steps of: irradiating the authenticityidentifying film with right-handed circularly polarized light orleft-handed circularly polarized light; and deciding that theauthenticity identifying film is authentic when either of right-handedcircularly polarized light and left-handed circularly polarized lightcan be detected and the other circularly polarized light cannot bedetected.

[0024] According to the present invention, a method of using anauthenticity identifying film including a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of at least incident light to produce reflected light,the reflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film including a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofat least incident light to produce reflected light, and a hologramforming layer laminated to the reflective film, having a hologramforming part that reflects circularly polarized light of circularpolarization opposite that of the reflected light in a directiondifferent from that of the reflected light to form a holographic image,the method comprising the steps of: irradiating the authenticityidentifying film with light including right-handed circularly polarizedlight and left-handed circularly polarized light; and deciding that theauthenticity identifying film is authentic when the holographic imagefrom the authenticity identifying film can be read from the authenticityidentifying film in a direction different from that of the reflectedlight.

[0025] According to the present invention, a method of using anauthenticity identifying film including a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of at least incident light to produce reflected light,the reflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film including a reflective film laminated to the reflectivefilm, having a circularly polarized light selectivity to reflect onlyeither of right-handed circularly polarized light and left-handedcircularly polarized light of at least incident light to producereflected light, and a hologram forming layer having a hologram formingpart that reflects circularly polarized light of circular polarizationopposite that of the reflected light in a direction different from thatof the reflected light to form a holographic image and laminated to thereflective film, the method comprising the steps of: irradiating theauthenticity identifying film with light including right-handedcircularly polarized light and left-handed circularly polarized light;and deciding that the authenticity identifying film is authentic whenthe film has a part that cannot be visually recognized when theauthenticity identifying film is observed visually through an examiningtool that transmits only either of right-handed circularly polarizedlight and left-handed circularly polarized light.

[0026] According to the present invention, a method of using anauthenticity identifying film including a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of at least incident light to produce reflected light,the reflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film including a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofat least incident light to produce reflected light, and a hologramforming layer laminated to the reflecting film, having a hologramforming part that reflects circularly polarized light of circularpolarization opposite that of the reflected light in a directiondifferent from that of the reflected light to form a holographic image,the method comprising the steps of: irradiating the authenticityidentifying film with light including right-handed circularly polarizedlight and left-handed circularly polarized light; and measuring thelight intensity difference between the intensities of right-handedcircularly polarized light and that of the intensity of left-handedcircularly polarized light transmitted by an examining tool thattransmits only either of right-handed circularly polarized light andleft-handed circularly polarized light and deciding whether or not theauthenticity identifying film is authentic on the basis of the lightintensity difference.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a typical sectional view of an authenticity identifyingfilm in an embodiment 1-1 according to the present invention;

[0028]FIG. 2 is a typical view of a cholesteric liquid crystal containedin an authenticity identifying film according to the present invention;

[0029]FIG. 3 is a graph showing, by way of example, anintensity-wavelength characteristic of reflected light reflected by anauthenticity identifying film according to the present invention;

[0030] FIGS. 4(A) and 4(B) are views of assistance in explaining anauthenticity identifying system employing an authenticity identifyingfilm according to the present invention;

[0031]FIG. 5 is a view of assistance in explaining a method of using anauthenticity identifying film in an embodiment 1-2 according to thepresent invention;

[0032]FIG. 6 is a typical sectional view of assistance in explaining amethod of using an authenticity identifying film in an embodiment 1-3according to the present invention;

[0033]FIG. 7 is a typical sectional view of an authenticity identifyingfilm in an embodiment 2-1 according to the present invention;

[0034]FIG. 8 is a plan view of an authenticity identifying film in anembodiment 2-2 according to the present invention;

[0035]FIG. 9 is a plan view of the authenticity identifying film in theembodiment 2-2;

[0036]FIG. 10 is a plan view of the authenticity identifying film in theembodiment 2-2;

[0037]FIG. 11 is a view of assistance in explaining a method of applyingan authenticity identifying film in an embodiment 2-3 according to thepresent invention to an article; and

[0038]FIG. 12 is a plan view of an article in an embodiment 2-4according to the present invention to be subjected to authenticityidentification and a circularly polarizing plate.

BEST MODE FOR CARRYING OUT THE INVENTION

[0039] First Embodiment

[0040] Preferred embodiments of the present invention will be describedhereinafter.

[0041] Embodiment 1-1

[0042]FIG. 1 is a sectional view of an authenticity identifying film inan embodiment 1-1 according to the present invention.

[0043] An authenticity identifying film 10 has a reflective film 11,aprotective layer 12, a light absorbing layer 13 and a base film 14.

[0044] The reflective film 11 reflects only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light. A hologram forming part 11 ais formed in one of the surfaces of the reflective film 11. The hologramforming part 11 a reflects light of the same circular polarization asthat of the reflected light reflected by the reflective film 11 in adirection different from that of the reflected light to form aholographic image. The reflective film 11 reflects only either ofright-handed circularly polarized light and left-handed circularlypolarized light on its surface contiguous with the protective layer 12or in the reflective film 11 to produce reflected light. Light of thesame circular polarization as that of the reflected light reaches thehologram forming part 11 a and is reflected on the hologram forming part11 a in a direction different from that of the reflected light by thehologram forming part 11 a to form a holographic image.

[0045] The reflective film 11 has a cholesteric liquid crystal phase.The mean screw axis orientation of the cholesteric liquid crystal phaseis parallel to the thickness of the film. Cholesteric liquid crystalwill be described later.

[0046] The reflective film 11 may be any one of mediums having opticalselective reflectivity and circularly polarized light selectivity, suchas polymer films formed through the fixation of cholesteric liquidcrystal orientation and films formed by dispersing a cholesteric liquidcrystal in mediums. A polymer film formed through the fixation of liquidcrystal orientation is particularly suitable.

[0047] A possible polymer film is formed by orienting a lowmolecular-weight liquid crystal in a cholesteric orientation and fixingthe cholesteric orientation by cross-linking the low molecular-weightliquid crystal by a photoreaction or a thermal reaction. Anotherpossible polymer film is formed by cholesteric-orienting a side chaintype or main chain type thermotropic high-molecular liquid crystal in aliquid crystal state, cooling the oriented thermotropic chain-molecularliquid crystal at a temperature not higher than the transition point tofix the oriented state of the liquid crystal. A third possible polymerfilm is formed by cholesteric-orienting a side chain type or a mainchain type lyotroic high-molecular liquid crystal in a solution andfixing the orientated state by gradually removing the solvent.

[0048] High-molecular liquid crystals suitable for forming such filmsare side chain type polymers having liquid crystal forming groups onside chains, such as polyacrylates, polymethacrylates, polysiloxanes andpolymalonates, and main chain type polymers having liquid crystalforming groups on main chains, such as polyesters, polyester amides,polycarbonates, polyamides and polyimides.

[0049] The hologram forming part 11 a is formed by embossing one surfaceof the reflective film 11 with minute irregularities with a masterhologram embossing die to transfer a pattern formed on the masterhologram embossing die to the surface. When embossing the surface of thereflective film 11, heat and pressure is applied to the reflective film11 by a press, a rolling mill, a calender, a laminator or a stamper.Another method applies a cholesteric liquid crystal to a master hologramdie in a cholesteric liquid crystal layer and orients the cholestericliquid crystal on the master hologram die. The hologram forming part 11a reflects light in a direction different from that of reflected lightreflected by the reflective film 11 to form a holographic image.

[0050] The protective layer 12 protects the reflective film 11. Suitablematerials for forming the protective layer 12 are acrylic resins,urethane resins, epoxy resins, silicone resins, EVA resins, polyamideresins, polyester resins, polystyrene resins, cellulose resins andmixtures of some of those resins. Materials of the protective layer 12are not limited to the foregoing resins. It is desirable to determine amaterial for forming the protective layer 12 selectively taking intoconsideration required properties of the surface of the authenticityidentifying film 10 including smoothness, hardness and abrasionresistance.

[0051] The light absorbing layer 13 absorbs light penetrating throughthe reflective film 11. The light absorbing layer 13 may be formed of,for example, a black ink. Since the light absorbing layer 13 absorbs thelight penetrating through the reflective film 11, undesirable reflectionof transmitted light can be prevented, which facilitates the visualrecognition of the holographic image.

[0052] From the view point of aesthetic design, the light absorbinglayer 13 may be a color layer formed of a color ink or the like andcapable of absorbing light in a specific waveband of the lightpenetrated the reflective film 11.

[0053] The base film 14 is provides the authenticity identifying film 10with a self-supporting ability. The material of the base film 14 may bedetermined according to a purpose of the authenticity identifying film10 and there is no particular restriction on the material of the basefilm 14. Particularly preferable materials for forming the base film 14are polycarbonates, polyvinyl alcohols, polysulfones, polyethylenes,polypropylenes, polystyrenes, polyarylates, polyethylene terephthalates,triacetyl cellulose, diacetyl cellulose, and poly(ethylene-co-vinylalcohol). The base film 14 may be a film of a mixture of one of theforegoing material and a high-molecular liquid crystal.

[0054]FIG. 2 is a typical view of a cholesteric liquid crystal containedin an authenticity identifying film according to the present invention,and FIG. 3 is a graph showing, by way of example, anintensity-wavelength characteristic of reflected light reflected by anauthenticity identifying film according to the present invention.

[0055] Explanation of Cholesteric Liquid Crystal

[0056] A cholesteric liquid crystal has elongated molecules parallel toeach other within the plane of a layer, but the direction of orientationis twisted slightly from layer to layer in the direction of thickness ofthe film to form a helix through the layers as shown in FIG. 2. When thepitch P (thickness necessary for liquid crystal molecules turn through360°) and the wavelength λ of the incident light is substantially equalto each other, the cholesteric liquid crystal exercises two opticalproperties, namely, a selective reflectivity and circular polarizationselectivity (Reference literature: Ekishyou to Disupurei Oyou no Kiso,Corona).

[0057] Selective refractivity is a property to reflect light in aspecific waveband more strongly than light of a wavelength in otherwaveband (FIG. 3). Since the selective reflectivity is exhibited for aspecific waveband, the reflected light has a chromatic color of a highcolor purity when a cholesteric liquid crystal having a proper pitch Pis selected. The center wavelength of the waveband λs and the bandwidthΔλ are expressed by Expressions (1) and (2).

λs=nm·P  (1)

Δλ=Δn·P/nm  (2)

[0058] where nm (={square root}{square root over ((no²+ne²)/2))}, ne isextraordinary ray reflective index in a plane in an optical medium, nois ordinary reflective index and Δn=ne−no.

[0059] The center wavelength λs and the bandwidth Δλ expressed byExpressions (1) and (2) are defined for vertical incidence of light onthe cholesteric liquid crystal layer (0°-incidence, on-axis incidence).If the incident light falls obliquely on the cholesteric liquid crystallayer (off-axis incidence), the pitch P decreases apparently and,consequently, the center wavelength λs shifts toward theshorter-wavelength side and the bandwidth Δλ decreases. This phenomenonis called blue shift because the center wavelength λs shifts toward theshorter-wavelength side. The shift of the center wavelength λs isdependent on the incident angle and is readily distinguishable by visualobservation. For example, reflected light from the cholesteric liquidcrystal is red when the cholesteric liquid crystal is observed in adirection perpendicular to the surface (direction of 0°-incidence). Asthe observation angle to a perpendicular to the surface increases, theobserved color of the reflected light changes from red, through orange,yellow, green, bluish green to blue.

[0060] The circular polarization selectivity is a property thattransmits circularly polarized light having a displacement vector thatrotates in a specific direction and reflects circularly polarized lighthaving a displacement vector that rotates in a direction opposite thespecific direction. Circularly polarized light included in the incidentlight and polarized in the same direction as that of twisting ofelongated molecules of the cholesteric liquid crystal is reflected andthe rotating direction of the reflected light becomes the same.Circularly polarized light included in the incident light and polarizedin a direction opposite the direction of twisting of elongated moleculesof the cholesteric liquid crystal is transmitted. These are the uniqueproperties of the cholesteric liquid crystal. A right-handed cholestericliquid crystal reflects a right-handed circularly polarized lightcomponent and transmits a left-handed polarized light component. Thereflected light is right-handed polarized light.

[0061] Explanation of Hologram

[0062] A hologram is a desired pattern, an image or characters formed bychanging the grading constant and the diffraction direction of adiffraction grating formed on an article in a small region correspondingto a pixel size. Holograms are classified by construction into volumeholograms and plane holograms, or by light modulating system intoamplitude holograms and phase holograms. Modulation plane holograms(embossed holograms) which can be mass-produced by a microreplicaprocess are used widely in industries. To form a sharp holographic imagein the visible region, the grating constant of the diffraction gratingmust be very precisely controlled so as to fall in the range of about 10μm to about 100 nm. Therefore, the fabrication of a master die and themanufacture of replicas require proficient processing techniques.

[0063] As shown in FIG. 3, the hologram reflects light of a wavelengthin a specific waveband strongly, authenticity identification can beachieved through the observation of the wavelength of the reflectedlight.

[0064] Using Method

[0065] FIGS. 4(A) and 4(B) are views of assistance in explaining anauthenticity identifying system employing the authenticity identifyingfilm according to the present invention. FIG. 4(A) is a typicalsectional view of the authenticity identifying film and FIG. 4(B) is aperspective view of the authenticity identifying film.

[0066] The authenticity identifying film 10 is attached to an article20, i.e., a subject of authenticity identification, with an adhesivelayer 45 (FIG. 7) by a thermal transfer method, a sealing method, athread method or a thermal transfer ribbon method. The article 20 is,for example, a plastic card, such as a credit card, a banking card or anID card, a security, such as a gift certificate, a currency note, a giftcheck or a stock certificate, a PET card, such as a prepaid card or acommuter ticket, tickets, a bank note, a passport or a betting ticket,which, however is not restrictive.

[0067] When the twisting direction of the cholesteric liquid crystalphase of the reflective film 11 is a right-hand direction(counterclockwise direction) and a light source 21 emits natural light,a detector 22 a disposed so as to receive regularly reflected lightreflected in a direction indicated by the arrow followed by a solid linereceives right-handed circularly polarized light of reflected lightreflected by the reflective film 11. In FIG. 4(A), the right-handedcircularly polarized light is shown, for convenience, as if the same isreflected only by the surface of the reflective film 11 contiguous withthe protective layer 12 to produce reflected light. Actually, thereflected light includes right-handed polarized light reflected by theinterior of the reflective film 11.

[0068] A detector 22 b disposed so as to receive reflected lightreflected in the direction of the arrow followed by a broken line isable to detect a holographic image formed by light component reflectedand diffracted by the hologram forming part 11 a formed in the othersurface of the reflective film 11. The light reflected by the hologramforming part 11 a right-handed circularly polarized light component,which is the same as the reflected light. If a circularly polarizingplate or a combination of a linearly polarizing plate and a phase filmis incorporated into the detector 22 a to distinguish the rotatingdirection of circularly polarized light, light is transmitted by aright-handed circularly polarizing plate and the same can be detected,and light is absorbed by a left-handed circularly polarizing plate andthe same cannot be detected. Thus, the reflected light can be readilyrecognized if the same is right-handed polarized light. Since anordinary reflector does not have circularly polarized light selectivity,the reflected light can be detected by using either of a right-handedcircularly polarizing plate and a left-handed circularly polarizingplate. According to the present invention, the authenticity of theauthenticity identifying film 10 can be easily distinguished by anauthenticity identifying system shown in FIGS. 4(A) and 4(B).

[0069] A band-pass filter for distinguishing the color of circularlypolarized light may be incorporated into the light source unit 21 or aband-pass filter or a spectroscopic system for distinguishing the colorof circularly polarized light may be incorporated into the detector 22 ato distinguish the wavelength selectivity of the reflective film 11.When the wavelength selectivity of the reflective film 11 can be thusdistinguished, it is possible to distinguish easily the authenticity ofthe authenticity identifying film 10 by examining the reflected light tosee whether or not the reflected light has a wavelength in a desiredwaveband. Electrooptic detection also is possible.

[0070] The hologram forming part 11 a of the reflective film 11 may beprovided with a ciphered authenticity identifying code represented bythe direction of diffraction or the wavelength of diffracted light. Theauthenticity of the authenticity identifying film 10 can be easilydistinguished by receiving a holographic image formed by the hologramforming part 11 a by the detector 22 b and distinguishing theauthenticity of the holographic image by an authenticity distinguishingdecoder 23 combined with the detector 22 b.

[0071] Authenticity can be more exactly distinguished by emittingcircularly polarized light by the light source unit 21. Whenright-handed circularly polarized light is emitted by the light sourceunit 21, cholesteric reflection can be observed by the detector 22 adisposed so as to receive regularly reflected light and a holographicimage can be observed by the detector 22 b disposed at a positiondisplaced from the passage of the regularly reflected light. Whenleft-handed circularly polarized light is emitted by the light sourceunit 21, no reflected light is produced, any holographic image is notformed and only the color of the light absorbing layer 13 can beobserved.

[0072] Thus, the authenticity identifying system may be provided, inaddition to the light source unit 21 and the detectors 22 a and 22 b,with the circularly polarizing plate, the linearly polarizing plate, thephase plate, the band-pass filter, the spectroscopic system and theauthenticity identifying decoder 23 to distinguish the rotatingdirection of the circularly polarized light included in the reflectedlight and the reflection waveband and to decode the authenticityidentifying code represented by the holographic image. When theauthenticity identifying system is provided with those additionalcomponents, the authenticity of the authenticity identifying film 10 canbe more accurately distinguished. Electrooptic detection also ispossible.

[0073] Since the reflective film 11 employed in this embodiment has thecholesteric liquid crystal phase, the reflected light from thereflective film 11 is the circularly polarized light. Therefore, theauthenticity of the authenticity identifying film 10 can be easilydistinguished by detecting the reflected light by the detector 22 aprovided with the circularly polarizing plate. Since the reflected lighthas a wavelength in a specific waveband, the authenticity of theauthenticity identifying film 10 can be easily distinguished throughvisual observation, and the authenticity can be more accuratelydistinguished by mechanical reading.

[0074] Since the reflective film 11 is provided with the hologramforming part 11 a in one surface thereof, the authenticity of theauthenticity identifying film 10 can be easily distinguished bydetecting a holographic image formed by diffracted light reflected bythe hologram forming part 11 a at a reflection angle other than theregular reflection angle by the detector 22 b.

[0075] Embodiment 1-2

[0076]FIG. 5 is a view of assistance in explaining a method of using anauthenticity identifying film in an embodiment 1-2 according to thepresent invention.

[0077] In the following description of the embodiment 1-2, partsfunctionally similar to those previously mentioned in the description ofthe embodiment 1-1 are designated by the same reference characters andthe description thereof will be omitted to avoid duplication.

[0078]FIG. 5 shows an article 20 to which an authenticity identifyingfilm 10 provided with a hologram forming part 11 a that forms a hologramof characters, pictures, patterns or the like.

[0079] When the article 20 is irradiated with natural light(nonpolarized light), reflected light from a part of the article towhich the authenticity identifying film 10 is attached is circularlypolarized light. When the twisting direction of the cholesteric liquidcrystal phase of the reflective film 11 is a right-hand direction(counterclockwise direction), the reflected light reflected by thereflective film 11 and a holographic image are right-handed circularlypolarized light. When the reflected light and the holographic image areobserved through a circularly polarizing plate 30 having a left-handcircularly polarizing part 30 a that transmits left-handed circularlypolarized light, and a right-hand circularly polarizing part 30 bdisposed contiguously with the left-hand circularly polarizing part 30a, transmitting right-handed circularly polarized light, the selectivelyreflected light reflected by the authenticity identifying film 10 andthe holographic image can be clearly observed through the right-handcircularly polarizing part 30 b as if there is no polarizing plate, theleft-hand circularly polarizing part 30 a becomes dark and neither thereflected light or the holographic image can be observed through theleft-hand circularly polarizing part 30 a. Therefore, it is readilyknown that the reflected light is right-handed circularly polarizedlight and the holographic image is formed of right-handed circularlypolarized light.

[0080] If the authenticity identifying film attached to the article is acounterfeit, the reflected light is not circularly polarized light norcan the holographic image formed of circularly polarized light beformed. Accordingly, when the authenticity identifying film 10 isobserved through the circularly polarizing plate 30, the sameselectively reflected light and the same holographic image can be seenthrough the left-hand circularly polarizing part 30 a and the right-handcircularly polarizing part 30 b.

[0081] The embodiment 1-2 is able to distinguish authenticity easily byusing the circularly polarizing plate 30.

[0082] Authenticity distinguishment can be more accurately achieved bythe electrooptical measurement of the difference or the ratio in theintensity of transmitted light between the left-hand circularlypolarizing part 30 a and the right-hand circularly polarizing part 30 bthan by the visual observation of the authenticity identifying film 10.The accuracy of authenticity distinguishment can be further improved bythe measurement of the wavelength of the detected reflected light.

[0083] Embodiment 1-3

[0084]FIG. 6 is a typical sectional view of assistance in explaining amethod of using an authenticity identifying film in an embodiment 1-3according to the present invention.

[0085] An authenticity identifying film 10 has a reflective film 11, aprotective layer 12, a light absorbing layer 13, a base film 14 and ahologram forming layer 15.

[0086] In this embodiment, both the surfaces of the reflective film 11are smooth, which is different from the reflective films employed in theembodiments 1-1 and 1-2.

[0087] The hologram forming layer 15 is laminated to the reflective film11 to reflect light penetrating through the reflective film 11 in adirection different from that of the reflected light from the reflectivefilm 11 to form a holographic image. One surface of the hologram forminglayer 15 is provided with a hologram forming part 15 a. The reflectivefilm 11 reflects either of right-handed circularly polarized light orleft-handed circularly polarized light. The hologram forming layer 15transmits circularly polarized light of one hand of polarizationopposite the other hand of polarization of the reflected light reflectedby the reflective film 11, and the hologram forming part 15 a reflectsthe light transmitting through the reflective film 11 to form aholographic image. The hologram forming layer 15 is formed of asynthetic resin that facilitate forming minute irregularities in thehologram forming layer 15. Synthetic resins suitable for forming thehologram forming layer 15 are thermoplastic synthetic resins includingpolyvinyl chlorides, acrylic resins, polycarbonates and polystyrenes,thermosetting synthetic resins including unsaturated polyester resins,melamine resins and epoxy resins, and mixtures each of a thermoplasticsynthetic resin and a thermosetting synthetic resin. The hologramforming layer 15 of such a resin is bonded to the reflective film 11.The hologram forming layer 15 may be formed by applying a solution ofsuch a resin or a molten resin to the surface of the reflective film 11.The hologram forming layer 15 may be formed on a transparent film byapplying a solution or a molten resin to the transparent film, and thetransparent film carrying the hologram forming layer 15 may be attachedto the surface of the reflective film 11.

[0088] The authenticity of the authenticity identifying film 10 in thisembodiment also can be easily distinguished.

[0089] Since the reflective film 11 and the hologram forming layer 15are separate components, the reflective film 11 and the hologram forminglayer 15 can be easily formed by separate processes, respectively.

[0090] Since the reflective film 11 and the hologram forming layer 15can be separately manufactured, different kinds of authenticityidentifying films 10 can be manufactured by combining one kind ofall-purpose reflective film 11 and hologram forming layers 15respectively having hologram forming parts 15 a of different patterns.

[0091] Modifications

[0092] The present invention is not limited in its practical applicationto the foregoing embodiments 1-1, 1-2 and 1-3, and many changes andmodifications are possible.

[0093] For example, the hologram forming parts 11 a and 15 a may beprovided with a plurality of fine irregular sections, each havinggrooves extended in different directions, respectively. Such a hologramforming part reflects reflected light in a plurality of directions andhence authenticity distinguishing accuracy can be improved by thedetection of the reflected light reflected in different directions.

[0094] Although the twisting direction of the elongated molecules of thecholesteric liquid crystal phase of the reflective films in theembodiments 1-1, 1-2 and 1-3 is right-handed, the same may beleft-handed for the same effects.

[0095] The hologram forming layers 11 a and 15 a may be provided with adeposited film to form a sharp holographic image.

[0096] Although the hologram forming part 11 a is formed in a surface ofthe reflective film 11 contiguous with the light absorbing layer 13 inFIG. 1, the hologram forming part 11 a may be formed in the surfacecontiguous with the protective layer 12. In such a case, light incidenton the authenticity identifying film 10 is reflected by the hologramforming part 11 a in a predetermined direction to form a holographicimage, and the light penetrating into the reflective film 11 isreflected in a direction different from that of the reflected lightreflected by the hologram forming part 11 a. Thus, the effect of thisauthenticity identifying film is the same as that of the authenticityidentifying film 10 shown in FIG. 1.

[0097] If the reflective film 11 is sufficiently hard, the protectivelayer 12 may be omitted.

[0098] If an article to which the authenticity identifying film 10 isattached has a light absorbing property, the light absorbing layer 13may be omitted.

[0099] If the reflective film 11, the protective layer 12 or the lightabsorbing layer 13 has a sufficient self-supporting ability or theauthenticity identifying film 10 need not have self-supporting ability,the authenticity identifying film 10 need not be necessarily providedwith the base film 14.

[0100] As is apparent from the foregoing description, according to thepresent invention, the reflective film provided with the hologramforming part is difficult to forge and facilitates the identification ofauthenticity.

[0101] The reflective film and the hologram forming layer attached tothe reflective film or sandwiched between the adjacent surfaces can bemanufactured by separate processes, respectively.

[0102] Since the reflective film is a liquid crystal film. the same hasa selective reflectivity and a circularly polarized light selectivity.

[0103] Since the reflective film is formed by fixing a cholestericphase, the reflective film has a selective reflectivity and a circularlypolarized selectivity.

[0104] The hologram forming part having an embossed hologram can beeasily formed.

[0105] The light source unit for illuminating the authenticityidentifying film and the detector for detecting the rotating directionof the circular polarized light facilitates authenticity identification.

[0106] The detector that detects only the light of a wavelength in apredetermined waveband simplifies authenticity identification.

[0107] The detector that detects the intensity of transmitted lightenables accurate authenticity identification.

[0108] The light source unit and/or the detector having the polarizingplate, the phase plate and or the band-pass filter can be easilymanufactured.

[0109] When the reflected light produced by reflecting right-handedcircularly polarized light and left-handed circularly polarized light isdetected, it is decided that the authenticity identifying film isauthentic when only either of the reflected light of the right-handedcircularly polarized light or that of the left-handed circularlypolarized light can be detected, so that authenticity can be easilydistinguished.

[0110] When the reflected light produced by reflecting light includingright-handed circularly polarized light and left-handed circularlypolarized light is detected, it is decided that the authenticityidentifying film is a counterfeit when only the reflected lightreflected in one direction can be detected and it is decided that theauthenticity identifying film is authentic when the reflected lightreflected in the different direction and the holographic image can bedetected. Therefore, authenticity can be easily distinguished.

[0111] When the authenticity identifying film is observed visuallythrough an examining tool that transmits only either of right-handedcircularly polarized light or left-handed circularly polarized light, itis decided that the authenticity identifying film is authentic. Thus,authenticity can be easily distinguished.

[0112] When light intensity difference is measured electrooptically byusing a measuring tool that transmits only either of right-handedcircularly polarized light or left-handed circularly polarized light, itis decided whether or not the authenticity identifying film is authenticon the basis of the light intensity difference. Thus, authenticity canbe accurately distinguished.

[0113] Second Embodiment

[0114] Embodiment 2-1

[0115] An authenticity identifying film in an embodiment 2-1 accordingto the present invention will be described with reference to FIG. 7.Referring to FIG. 7, an authenticity identifying film 40 has areflective film 41, a hologram forming layer 43 laminated to thereflective film 41, an adhesive layer 45 formed on the hologram forminglayer 43, an additional adhesive layer 42 formed on a surface of thereflective film 41 opposite the surface on which the hologram forminglayer 43 is laminated, and a base film 44.

[0116] The authenticity identifying film 40 is attached to an article 20with the adhesive layer 45. The hologram forming layer 43 has a hologramforming part 43 a. A hologram forming part may be formed in thereflective film 41 and the hologram forming layer 43 may be omitted.

[0117] The authenticity identifying film 40 is of a sealed type or alaminated type. The base film 44 remains on the authenticity identifyingfilm 40 after the authenticity identifying film 40 has been bonded tothe article 20.

[0118] The authenticity identifying film 40 may be of a hot-stampingtype or of a thermal transfer ribbon type. When the authenticityidentifying film 40 is of a hot-stamping type or a thermal transferribbon type, the base film 44 is removed after the authenticityidentifying film 40 has been bonded to the article 20 and hence theauthenticity identifying film 40 is provided with a separating layer anda protective layer instead of the additional adhesive layer 42.

[0119] The authenticity identifying film 40 may be provided withadditional layers other than the foregoing layers.

[0120] Embodiment 2-2

[0121] An embodiment 2-2 according to the present invention will bedescribed with reference to FIGS. 8 to 10.

[0122] Referring to FIG. 8, the authenticity identifying film 40 shownin FIG. 7 is attached to an article 20, such as a plastic card or abanking card, by a hot-stamping process, a sticking process or a thermaltransfer process. The surface of the article 20 is coated with, forexample, a black light absorbing layer to enable the effectiveobservation of the reflected light reflected by the reflective film 41and the holographic image formed by the hologram forming layer 43.Characters and a pattern 50 may be formed on the surface of theauthenticity identifying film 40.

[0123] If an effort is made to separate the authenticity identifyingfilm 40 stuck to the article 20 by a sticking process from the article20, the reflective film 41 is delaminated because the adhesions betweenthe component layers of the authenticity identifying film 40 and theadhesion between the authenticity identifying film 40 and the article 20are higher than the strength of the reflective film 41. Thus, thereflective film 41 is delaminated if an effort is made to separate theauthenticity identifying film 40 from the article 20 with an intentionto manipulate the authenticity identifying film 40 for dishonestalteration and hence dishonest alteration of the authenticityidentifying film 40 is impossible.

[0124] A modification will be described with reference to FIG. 9. Amodification shown in FIG. 9 has the authenticity identifying film 40,the article 20 and a photograph sandwiched between the authenticityidentifying film 40 and the article 20. The modification shown in FIG. 9is the same in other respects as the embodiment shown in FIG. 8. Asshown in FIG. 9, the photograph 51 enables the identification of theowner of the article 20. If the authenticity identifying film 40 isseparated from the article 20 with an intention replacing the photographwith another one, the reflective film 41 is delaminated.

[0125] The authenticity identifying film 40 employed in the modificationshown in FIG. 9 is not provided with any light absorbing layer (FIG. 7),the authenticity identifying film 40 is transparent and hence thephotograph 51 attached to the article can be surely recognized throughthe authenticity identifying film 40.

[0126] Another modification will be described with reference to FIG. 10.In the modification shown in FIG. 10, characters and patterns 50 areformed over the entire surface of an article 20, and an authenticityidentifying film 40 of the same size as the article 20 is laminated tothe article 20. The modification shown in FIG. 10 is the same in otherrespects as that shown in FIG. 9.

[0127] Embodiment 2-3

[0128] An embodiment 2-3 according to the present invention will bedescribed with reference to FIG. 11. FIG. 11 is a view of assistance inexplaining a method of applying an authenticity identifying film 48 toan article 20.

[0129] As shown in FIG. 11, a transfer sheet 47 having a base film 47 aand a transfer layer 47 b is disposed on the article 20, and a hotstamper or a transfer head 46 is lowered from above the transfer sheet47 (FIG. 11(a)). The hot stamper or the transfer head 46 applies heatand pressure to the transfer sheet 47 to transfer a part of the transferlayer 47 b to the article 20. In this manner, an authenticityidentifying film 48 is formed on the article 20 by the part of thetransfer layer 47 b.

[0130] The authenticity identifying film 48 has a separating layer and aprotective layer 42, a reflective film 41, a hologram forming layer 43and an adhesive layer 45 (FIG. 7).

[0131] Embodiment 2-4

[0132] An embodiment 2-4 according to the present invention will bedescribed with reference to FIG. 12. The embodiment shown in FIG. 12 isa card formed by attaching the circularly polarizing plate 30 shown inFIG. 5 to a plastic or paper base 32. The circularly polarizing plate 30has a left-hand circularly polarizing part 30 a, a right-hand circularlypolarizing part 30 b, and a support part 31 disposed at the boundarybetween the left-hand circularly polarizing part 30 a and the right-handcircularly polarizing part 30 b.

[0133] Each of the left-hand circularly polarizing part 30 a and theright-hand circularly polarizing part 30 b is formed by laminating apolarizing film and a phase contrast film. The phase contrast film is onthe side of an authenticity identifying film. The directions of theabsorption axes of the polarizing films of the left-hand circularlypolarizing part 30 a and the right-hand circularly polarizing part 30 bare perpendicular to each other. The strength of the circularlypolarizing plate 30 is maintained by the support part 31.

[0134] The circularly polarizing plate 30 has a visual effect as shownin FIG. 5. When the photograph of the embodiments shown in FIGS. 9 and10 are observed (FIG. 9), the left-hand circularly polarizing part 30 aconceals the holographic image and only the photograph can be observed,and the right-hand circularly polarizing part 30 b emphasizes theholographic image (FIG. 10).

1. An authenticity identifying film comprising: a reflective film havinga circularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of incident light to produce reflected light, whereinthe reflective film is provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image.
 2. An authenticityidentifying film comprising: a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light; and a hologram forming layerlaminated to the reflective film, having a hologram forming part thatreflects circularly polarized light of the opposite circularpolarization to that of the reflected light in a direction differentfrom that of the reflected light to form a holographic image.
 3. Theauthenticity identifying film according to claim 1 or 2, wherein thereflective film is a liquid crystal film.
 4. The authenticityidentifying film according to claim 3, wherein the reflective film has afixed cholesteric phase.
 5. The authenticity identifying film accordingto claim 1 or 2, wherein the hologram forming part includes an embossedhologram.
 6. The authenticity identifying film according to claim 1 or 2further comprising: an adhesive layer to be attached to an article. 7.The authenticity identifying film according to claim 6, wherein thereflective film is destroyed when the authenticity identifying film isseparated from the article.
 8. The authenticity identifying filmaccording to claim 6 further comprising: a protective film covering asurface of the reflective film opposite a surface of the reflective filmfacing an article.
 9. The authenticity identifying film according toclaim 6 further comprising: a base film attached by an additionaladhesive layer to a surface of the reflective film opposite a surface ofthe reflective film facing the article.
 10. The authenticity identifyingfilm according to claim 6 further comprising: a light absorbing layerinterposed between the reflective film and the adhesive layer.
 11. Anarticle with an authenticity identifying film comprising: anauthenticity identifying film comprising a reflective film having acircularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of incident light to produce reflected light, thereflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film comprising a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light, and a hologram forming layerlaminated to the reflective film, having a hologram forming part thatreflects circularly polarized light of the opposite circularpolarization to that of the reflected light in a direction differentfrom that of the reflected light to form a holographic image; an articleto which the authenticity identifying film is bonded; and a photographinterposed between the article and the authenticity identifying film.12. An authenticity identifying system comprising: an authenticityidentifying film comprising a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light, the reflective film beingprovided with a hologram forming part that reflects circularly polarizedlight of the same circular polarization as that of the reflected lightin a direction different from that of the reflected light to form aholographic image, or an authenticity identifying film comprising areflective film having a circularly polarized light selectivity toreflect only either of right-handed circularly polarized light andleft-handed circularly polarized light of incident light to producereflected light, and a hologram forming layer laminated to thereflective film, having a hologram forming part that reflects circularlypolarized light of the opposite circular polarization to that of thereflected light in a direction different from that of the reflectedlight to form a holographic image; a light source unit for irradiatingthe authenticity identifying film with light; and a detecting unit fordetecting the reflected light from the authenticity identifying film andthe holographic image.
 13. The authenticity identifying system accordingto claim 12, wherein the detecting unit is capable of detecting onlylight in a predetermined waveband.
 14. The authenticity identifyingsystem according to claim 12, wherein the detecting unit is capable ofmeasuring the intensity of transmitted light by the detecting unit. 15.The authenticity identifying system according to claim 12, wherein atleast either the light source unit or the detecting unit is providedwith a polarizing plate, a phase plate or a band-pass filter.
 16. Amethod of using an authenticity identifying film comprising a reflectivefilm having a circularly polarized light selectivity to reflect onlyeither of right-handed circularly polarized light and left-handedcircularly polarized light of incident light to produce reflected light,the reflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film comprising a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light, and a hologram forming layerlaminated to the reflective film, having a hologram forming part thatreflects circularly polarized light of circular polarization oppositethat of the reflected light in a direction different from that of thereflected light to form a holographic image; said method comprising thesteps of: irradiating the authenticity identifying film withright-handed circularly polarized light and left-handed circularlypolarized light respectively; and deciding that the authenticityidentifying film is authentic when either right-handed circularlypolarized light or left-handed circularly polarized light, which isreflected from the reflective film, can be detected and the othercircularly polarized light, which is not reflected from the reflectivefilm, cannot be detected.
 17. A method of using an authenticityidentifying film comprising a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light, the reflective film beingprovided with a hologram forming part that reflects circularly polarizedlight of the same circular polarization as that of the reflected lightin a direction different from that of the reflected light to form aholographic image, or an authenticity identifying film comprising areflective film having a circularly polarized light selectivity toreflect only either of right-handed circularly polarized light andleft-handed circularly polarized light of incident light to producereflected light, and a hologram forming layer laminated to thereflective film, having a hologram forming part that reflects circularlypolarized light of circular polarization opposite that of the reflectedlight in a direction different from that of the reflected light to forma holographic image; said method comprising the steps of: irradiatingthe authenticity identifying film with light including right-handedcircularly polarized light and left-handed circularly polarized light;and deciding that the authenticity identifying film is authentic whenthe holographic image from the authenticity identifying film can be readin a direction different from that of the reflected light.
 18. A methodof using an authenticity identifying film comprising a reflective filmhaving a circularly polarized light selectivity to reflect only eitherof right-handed circularly polarized light and left-handed circularlypolarized light of incident light to produce reflected light, thereflective film being provided with a hologram forming part thatreflects circularly polarized light of the same circular polarization asthat of the reflected light in a direction different from that of thereflected light to form a holographic image, or an authenticityidentifying film comprising a reflective film having a circularlypolarized light selectivity to reflect only either of right-handedcircularly polarized light and left-handed circularly polarized light ofincident light to produce reflected light, and a hologram forming layerlaminated to the reflective film, having a hologram forming part thatreflects circularly polarized light of circular polarization oppositethat of the reflected light in a direction different from that of thereflected light to form a holographic image; said method comprising thesteps of: irradiating the authenticity identifying film with lightincluding right-handed circularly polarized light and left-handedcircularly polarized light; and deciding that the authenticityidentifying film is authentic when the film has a part that cannot bevisually recognized when the authenticity identifying film is observedvisually through an examining tool that transmits only either ofright-handed circularly polarized light and left-handed circularlypolarized light.
 19. A method of using an authenticity identifying filmcomprising a reflective film having a circularly polarized lightselectivity to reflect only either of right-handed circularly polarizedlight and left-handed circularly polarized light of incident light toproduce reflected light, the reflective film being provided with ahologram forming part that reflects circularly polarized light of thesame circular polarization as that of the reflected light in a directiondifferent from that of the reflected light to form a holographic image,or an authenticity identifying film comprising a reflective film havinga circularly polarized light selectivity to reflect only either ofright-handed circularly polarized light and left-handed circularlypolarized light of incident light to produce reflected light, and ahologram forming layer laminated to the reflective firm, having ahologram forming part that reflects circularly polarized light of theopposite circular polarization to that of the reflected light in adirection different from that of the reflected light to form aholographic image; said method comprising the steps of: irradiating theauthenticity identifying film with light including right-handedcircularly polarized light and left-handed circularly polarized light;and measuring a light intensity difference between intensities ofright-handed circularly polarized light and that of left-handedcircularly polarized light transmitted by an examining tool thattransmits only either of right-handed circularly polarized light andleft-handed circularly polarized light; and deciding whether or not theauthenticity identifying film is authentic on the basis of the lightintensity difference.